Electrosurgical medical devices generally fall into one of two categories: monopolar medical devices and bipolar medical devices. A monopolar medical device includes an active electrode electrically connected to an electrosurgical generator. A return electrode, typically in the form of a patient pad, is also electrically connected to the electrosurgical generator and can be placed in contact with a patient. In use, electrical current is passed from the electrosurgical generator to the active electrode, through a site or a region of the patient's anatomy (i.e., a tissue or a vessel) to the patient pad, and back to the electrosurgical generator.
A bipolar medical device includes an active electrode and a return electrode adjacent the active electrode, both of which are electrically connected to an electrosurgical generator. In use, a site or a region of the anatomy is placed between the active and return electrodes, and electrical current passes from the electrosurgical generator to the active electrode, through the site or a region of the anatomy to the adjacent return electrode, and then back to the electrosurgical generator.
Examples of electrosurgical medical devices may be found in U.S. Pat. Nos. 4,196,734; 5,807,392; 7,211,079; 7,276,068; 7,922,713; 8,382,748; 8,491,578 and U.S. Patent Application Publication No. 2010/0331621 all of which are incorporated by reference herein in their entirety for all purposes.
While both monopolar and bipolar medical devices are desirable for use in various medical procedures, both have inherent shortcomings, however. For example, monopolar medical devices are known to pass relatively high electrical currents through the patient, which may cause unwanted tissue and/or organ damage. Moreover, some procedures cannot allow the use of monopolar medical devices because of high thermal spread and dispersed energy format. While bipolar medical devices minimize these shortcomings, accurately controlling which electrode is the active electrode is difficult.
It would therefore be desirable to have a medical device that can address at least one of the aforementioned shortcomings. For example, it would be attractive to have a single electrosurgical medical device that can be used in both monopolar and bipolar modes. It would be desirable to have an electrosurgical medical device that can be quickly switch between a monopolar mode and a bipolar mode. It would be advantageous to have medical device that can be used in a variety of arrangements in each mode. It would be attractive to have an electrosurgical medical device that uses less power and voltage, and therefore less current to perform a device function. It would be attractive to have an electrosurgical medical device with a plurality of electrodes, in which one or more of the electrodes are resistively heated to allow for thermionic disassociation of the electrons, ions, or both so that electrons, ions, or both in a field are accelerated. In this regard, it would be desirable because less voltage may be required to get the same disassociation of the electrons, ions, or both than with only voltage.